Anti-Arthritic and Anti-Inflammatory Potential of Spondias mangifera Extract Fractions: An In Silico, In Vitro and In Vivo Approach

Abstract

The fruits of Spondias mangifera (S. mangifera) have traditionally been used for the management of rheumatism in the northeast region of India. The present study explores the probable anti-arthritis and anti-inflammatory potential of S. mangifera fruit extract's ethanolic fraction (EtoH-F). To support this study, we first approached the parameters in silico by means of the active constituents of the plant (beta amyrin, beta sitosterol, oleonolic acid and co-crystallised ligands, i.e., SPD-304) via molecular docking on COX-1, COX-2 and TNF-α. Thereafter, the absorption, distribution, metabolism, excretion and toxicity properties were also determined, and finally experimental activity was performed in vitro and in vivo. The in vitro activities of the plant extract fractions were evaluated by means of parameters like 1,1-Diphenyl-2- picrylhydrazyl (DPPH), free radical-reducing potential, albumin denaturation, and protease inhibitory activity. The in vivo activity was evaluated using parameters like COX, TNF-α and IL-6 inhibition assay and arthritis score in Freund Adjuvant (CFA) models at a dose of 400 mg/kg b.w. per day of different fractions (hexane, chloroform, alcoholic). The molecular docking assay was performed on COX-1, COX-2 and TNF-α. The results of in vitro studies showed concentration-dependent reduction in albumin denaturation, protease inhibitors and scavenging activity at 500 µg/mL. Administration of the S. mangifera alcoholic fraction at the abovementioned dose resulted in a significant reduction (p < 0.01) in arthritis score, paw diameters, TNF-α, IL-6 as compared to diseased animals. The docking results showed that residues show a critical binding affinity with TNF-α and act as the TNF-α antagonist. The alcoholic fraction of S. mangifera extract possesses beneficial effects on rheumatoid arthritis as well as anti-inflammatory potential, and can further can be used as a possible agent for novel target-based therapies for the management of arthritis.

Keywords: Spondias mangifera; anti-inflammatory; arthritis; in silico; in vitro and in vivo.

Figure 1

2D representation of docked conformation of TNF-α with ligands obtained after glide XP docking. Green dashed lines represent conventional hydrogen bonds with the interacting amino acid residues. Pink lines indicate hydrophobic (alkyl–alkyl, π–alkyl or π–π) interactions.

Figure 2

3D representation of docked conformation of TNF-α with ligands obtained after Glide XP docking.

Figure 3

The figure shows that no compounds cross blood–brain barrier. Among these compounds, the compounds gallic acid and caffeic exhibit the best ADME properties.

Figure 4

Effect of S. mangifera ethanolic fraction on TNF-α. Results are expressed as mean ± SEM (n = 6) and analysed by one-way ANOVA followed by Dunnet’s test. ** p < 0.01 = significant when compared with group I. ^## p < 0.01, * p < 0.05 = significant when compared with group II. ^ns p > 0.05 = non-significant when compared with group II.

Figure 5

Effect of S. mangifera ethanolic fraction on IL-6. Results are expressed as mean ± SEM (n = 6) and analysed by one-way ANOVA followed by Dunnet’s test. ** p < 0.01 = significant when compared with group I. ^## p < 0.01, * p < 0.05 = significant when compared with group II. ^ns p > 0.05 = non-significant when compared with group II.

Figure 6

Percentage inhibition of DPPH scavenging activity of S. mangifera fruit fractions. Data are presented as the mean value ± SEM (n = 3).

Figure 7

Reduced potential scavenging activity of different fractions of S. mangifera fruit extract.

Figure 8

Effect of S. mangifera ethanolic fraction against protein denaturation using egg albumin. Data are expressed as means ± SEM (n = 3), with a significance test for comparison with aspirin using ANOVA followed by Dunnet’s ‘t’ test. ** p < 0.01, ^## p < 0.05 and ^ns p > 0.05: non-significant.

Figure 9

Effect of S. mangifera ethanolic fraction against protein denaturation using egg albumin. Data are expressed as means ± SEM (n = 3), with a significance test for comparison with aspirin using ANOVA followed by Dunnet’s ‘t’ test. ** p < 0.01, ^## p < 0.5 and ^ns p > 0.05: non-significant.

Figure 10

Effects of S. mangifera ethanolic fraction on CFA-induced arthritis in mice. All values are expressed as Mean = SEM (n = 6). ** p < 0.01= significant when compared with group I. ^## p < 0.01 and * p < 0.05 = significant when compared with group II. ^ns p > 0.05: non-significant when compared with group II.

Figure 11

Effects of S. mangifera ethanolic fraction on CFA-induced arthritis in mice. All values are expressed as Mean = SEM (n = 6), ** p < 0.01 = significant when compared with group I. ^## p < 0.01 and * p < 0.05 = significant when compared with group II. ^ns p > 0.05: non-significant when compared with group II.